Inhibiting the dissolution of the intermediate with conductive polymer coating layer to improve the stability of CuTCNQ cathode for K-ion batteries

The seriously dissolution of the intermediate into the organic electrolyte has been the key limitation for metal-organic compounds in K-ion batteries. Here, we initially inhibit the dissolution of intermediate products (TCNQ 0 ) with a highly conducting polymer (polypyrrole, PPy) coated on the CuTCNQ. And the adsorption energy between the conductive polymer PPy and the intermediate product TCNQ can be significantly enhanced (−0.55 eV) as compared to the TCNQ molecules (0.21 eV), which can restrain the free intermediate product dissolved in the organic electrolyte, resulting in an enhanced cyclic stability as well as rate performance. Additionally, the highly conductive PPy exhibits flexible structure, which can weaken the interface effect between the electrode and the coating layer. This work provides further understanding on surface coating on metal-organic compounds and has significant basic scientific sense for the in-depth research of K-ion batteries.